Apparatus for opening tubes of flexible material

ABSTRACT

A method and apparatus for spreading open the ends of bag tube blanks in a bag forming machine wherein a pair of opposing suction cups, one on each side of the path of movement of the blanks are moved in a circular path with respect to the machine frame. At the same time the suction cups are counter rotated at the same angular speed but in directions opposite to their movement in the circular path whereby the suction cup faces maintain constant their angular relationship with respect to the machine frame. The paths of movement of the cups are selected to provide concurrent tangential passage of the cups with the two walls of the bag blank and a suction pressure is applied to the cups when they are in contact with the blank. The blank is opened by action of the suction pressure as the cups move away from each other.

United States Patent [191 [111 3,913,463 Hollis [451 Oct. 21, 1975APPARATUS FOR OPENING TUBES OF Primary Examiner-1oseph H. McGlynnFLEXIBLE MATERIAL [75] Inventor: Clinton R. Hollis, Camden, Ark.

[73] Assignee: lnternationalPaper Company, New

York, NY,

[22] Filed: July 5, 1974 [21} Appl. No.: 485,700

Related US. Application Data [62] Division of Ser. No. 267,361, June 29,1972, Pat.

[52] US. Cl 93/28; 53/386; 93/84 FF [5]] Int. Cl. B31B 1/80 [58] Fieldof Search 93/14, l5, 16, 22, 23, 93/24, 25, 28, 29, 30, 84 FF; 53/386;226/47 [56] References Cited UNITED STATES PATENTS 3,446,121 5/1969Achelpohl 93/28 3,545,346 12/1970 Achelpohl 93/28 3,547,010 12/1970Gennerich et al. 93/28 X Assistant Examiner-James F. Coan Attorney,Agent, or Firm-R. S. Sanborn; W. T. Zielinski; W. A. Aguele [5 7]ABSTRACT A method and apparatus for spreading open the ends of bag tubeblanks in a bag forming machine wherein a pair of opposing suction cups,one on each side of the path of movement of the blanks are moved in acircular path with respect to the machine frame. At the same time thesuction cups are counter rotated at the same angular speed but indirections opposite to their movement in the circular path whereby thesuction cup faces maintain constant their angular relationship withrespect to the machine frame. The paths of movement of the cups areselected to provide concurrent tangential passage of the cups with thetwo walls of the bag blank and a suction pressure is applied to the cupswhen they are in contact with the blank. The blank is opened by actionof the suction pressure as the cups move away from each other.

5 Claims, 4 Drawing Figures I VACUUM SOURCE US. Patent Oct. 21, 1975Sheet 1 of 2 3,913,463

VACUU M 7 SOURCE VACUU SOURCE CAM OPERATED PNEUMATIC VALV E CAMPNEUMATIC.

VALVE OPERATED US. Patent Oct. 21, 1975 Sheet20f2 3,913,463.

This is a divisional of Ser. No. 267,361 filed June 29, 1972, now US.Pat. No. 3,834,287.

BACKGROUND OF THE INVENTION This invention pertains to a method andapparatus for spreading open the walls of an essentially flat tube offlexible material and more particularly relates to a method andapparatus for spreading open the walls of paper tube blanks in a bagforming machine.

There'are various known embodiments of bag forming machines for formingbags from tube stock of flexible material such as kraft paper. Usually,the bag blanks are separately made by a tubing machine which provides acontinuous tube having a longitudinal seam prepared from sheet stock andcuts the tube to a series of blanks of predetermined length suitableforthe bag to be formed. These blanks are then processed through a bagforming machine for forming at least one sealed end.

The machine is adapted to process a large volume of bag blanks. Thus,the blanks are continuously fed irito the machine which includes meansfor transporting the bag blanks in series manner through severalstations where the various operations for formingthe bag bottom areautomatically performed. The blank is first scored lightly to providethe fold lines necessary for forming the bottom while the tube is in anessentially flat condition in one plane. The bottom end of the tube isthen partially folded along a line transverse to the tube while the twowalls of the ends still remain adjacent each other. These walls are thenspread openand folded into the plane of the blank to provide exposedinner surfaces of the end portion. A suitable cement is then rollerapplied to the exposed surfaces and additional folding is performed toprovide the necessary overlying layers of the tube end to form thebottom of 'the bag.

A typical prior art bag forming machineis described in greater detail inUS. Pat. No. 2,707,421 to M. Rawe. As illustrated in FIG. of that patentthe tube end is first partially opened by suction devices 3; thespreader finger 4 enters between the partially opened walls and opensthem further; Then, the bow shaped forming members 5 enterthe partiallyopened tube end to fold the tube walls into the plane of the tubeblank.

{This type of tube end spreading mechanism is quite common in prior artbag forming machines. In some machines the spreader finger is omitted.

- 'A serious problem associated with such prior art spreading mechanismsis that the suction devices occasionally do not pre-open the tube endssufficiently. In such instances, the spreader finger or the bow shapedforming members crush the end of the bag blank whereby a malformed bagis produce. Since the suction devices move around a circular path theirfaces are jointly parallel with the walls of the bag tube at only onepoint in their paths of motion. This is at their point of contact withthe tube walls. Thus, as the suction devices approach the tube wallsthey form a distinct angle which decreases until contact is made andthen they as sume a departing angular relationship as'they rotatev Also,.,these dynamics operate as aconstraint on the usefulness of themachinesince when bag sizes are made which depart from the optimum or nominaldesign size upon1 which the geometry of the spreading mechanism ispredicated, the rejection rate if further increased. 1

Several attempts have been made to solve this problem among which isincreasing the radius of the arc of movement of the suction devices sothat they contact the tube end walls with a distinct interference orforce against each other, to enhance the likelihood ofa'firm vacuumgrasp. This results in premature wear of the forward corner of thevacuum cups having the adverse effect of increasing the down-time of themachine. Other attempts include reducing the size of the vacuum cup inan effort to alleviate the corner wear problem while increasing thevacuum pressure. It was found that this did not sufficiently increasethe effectiveness of the vacuum devices to substantially reduce theobjectionable rejection rate.

The invention as herein described solves the aforementioned problems byproviding a far superior dynamic operation of the spreading mechanismwherein the suction cups approach each other while maintainingtheirfaces in essentially contant angular relationship, perform theirspreading function, and move away from each other with their faces inessentially .unchanged angular relationship. The invention has beenfound so effective that when making certain select sizes of bags fromrelatively heavy stock it is possible to omit one of the rotatingsuction devices and replace. it merely by a wall against which the bagtube end may rest while it. is partially opened by the remaining suctiondevice.

SUMMARY One aspect of the present invention resides in a method ofspreading open the walls of a tube of flexible material, including firstand. second walls essentially facing each other wherein the tube is inmotion in a predetermined direction, including the steps of; contactingthe first wall of the tube with the suction face of a suction cupwherein the face-is essentially parallel to the walls of the tube, andmoving the suction cup at least in part during the contacting stepin adirection having at least a vector component parallel to saidpredetermined direction of movement of the tube. The method includes thefurther steps of; applying a suction pressure to the suction cup atleast inv part during the contacting step, and moving the suction cup ina direction away from the first wall while applying the suction pressureand while maintaining the suction cup face essentially parallel to thewalls of the tube, thereby moving the first wall in a direction awayfrom the second wall by action of the suction pressure.

In a preferred version of the method of the invention a pair of opposingsuction cups are employed with the steps including; contacting thewallsof the tubewith the respective suction faces of the cups, one on eachside of the tube, wherein the facesof the cups are essentiallyparallel,and moving the suction cups at least in part during'the contacting stepin a direction of movement of the tube. This version of themethodincludes thefurther steps of; applying a suction pressure otherwhile applying the suction pressure and while Yet another aspect of theinvention resides in an apparatus-combination contemplated foruse inconnectionwith a bag forming machine wherein the' machine includes aframe, means in the frame for folding the ends of the bag'tube blanktoprovide a plurality of overlying layers thereof while the" end of thetubeis in motion, means in the machine frame for moving the end of thetube into'the folding means in a determined direction to perform thefolding, and mean's'operatively coupled with thefolding means forsecuring the overlying' layers to form the bag bottom. The preferredapparatus combination in accordance with the present invention isoperatively coupled with the folding'means and is for openingthe end ofthe tubewhile the end is in motion in the aforementioned direction priorto completion of the folding thereof. This app'artuscombinationincludes; a pair of suction cups, a first support member,means for rotating one of the suction cups at a' predetermined angularvelocity about a first axis which is positioned inthe'first supportmember, and means for rotating'the support member at an angular velocitysubstantially equal to but opposite in direction to the predeterminedangular velocity about an axis second which is positioned in the machineframe essentially parallel to the first axis and positioned to providean essentially tangential passage of the suction face of the first cupwith a first wall of thetube end in substantially the same direction asthe predetermined direction of movement of the tube end.

The apparatus further includes; a second support member, means forrotating the second suction cup about an axis third which is positionedin the second support member, means for rotating the second supportmember in synchronism' with the first support member at an angularvelocity substantially equal to 'but opposite indirection to therotation of the second suction cup about the axis third, the rotation ofthe second support member being about an axis fourth which is positionedin the machine frame essentially parallel to the axis third andpositioned to provide an essentially tangential passage of the suctionface of the second cup with a second wall of the tube end in thevicinity of,

substantia'lly'in the same directionand concurrent with,

- themselves or with the tube end wallsthroughout their respective pathsofmotion. Thus, the suction cups can be initially se'tin parallelrelationship ,with thetubewall path and they will maintain thisrelationship throughout their respective motions. This resultsvingreatly improved vacuum'contact with the tube walls. 4,

Furthermore, there is little .or no. transverse- -movement of thesuction cups with respect-to .the tube walls while they are in contacttherewith resulting insubstantially less wear of the cup faces.

v 'Kfurther advantage of the invent-ion resides in doing away with thenecessity of employing the conventional rotating vacuum couplingsassociated with the prior art tube end spreading devices for providing avacuum through the drive shafts of the vacuum cups.'Since the vacuumcups of .the .present invention do'not rotate with respect to themachine frame, a suction source can be directly coupled to the cups.This further increases the reliability ofthe machine. Another advantageof the invention is that bag tubes having minor inside sticking problemsassociated with the. longitudinal glued joint can beeffectively opened.Also, it can be understood that the invention results in a much widerpre-opening ofthe. bag tube than heretofore obtained.

In view of the foregoing it isan object of the present ,inventionto'provideimproved methods and apparatus for spreading open thewalls ofa tube of flexible material.

' It is another object of the invention to provide a method andapparatus of improved effectiveness for spreading open the walls of atube of paper-like material in connection with bag making machines.

It is another object of "the invention to provide method and apparatusimprovements which reduce the rejection rate of bags made by a bagmaking machine.

It is another object of the invention to provide an improved method andapparatus for the vacuum opening of the walls of a bag tube'blankenabling the use of vacuum cups of enlarged face area. I It'isyetanother object of the present invention to provide an improved methodand apparatus for the vacuum opening of the walls of a bag tube blank ina bag making machine for reducing the wear of the vacuum cups andreducing the downtime of the machine. It is another object of theinvention to providev iniproved apparatus for the vacuum opening of abag tube enabling the use of a more simplified vacuum coupling system. v

It is yet a further object of the invention to provide an improvedapparatus for the vacuum opening of a bag tube blank for use in a bagmaking machine extending the flexibility of usefulness of the machine.

These and other objects, advantagesand features of the invention, willbe more fully understood by referring to the following descriptions andclaims, taken in conjunction with the accompanying-drawings.

BRIEF DESCRIPTION or THE DRAWINGS FIG. 1 is a fragmentary, perspectiveview, partly in section, of a portion of the inlet end of a bag making Imachine illustrating the prior art apparatus for opening the end of abag tube.

FIG. 2 is a cross-sectional view taken in the direction 2 2 of FIG. 1wherein the apparatus for opening the bag tube ends is replaced byimproved apparatus illustrating features of the present invention.

FIG. 3 is an endview, partly in section, of FIG. 2 in the direction 3 3,illustratingin'greater detail the FIG.,,3 illustrating in still furtherdetail the drive mecha- -nism for the tube suction cups.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIG. 1, whichpartly illustrates the inlet protion of a bag making machine,essentially flat bag tube blanks 12 are sequentially introduced into themachine by conventional feeding apparatus not shown. It will beunderstood that as used herein the term essentially flat is intended todescribe the relaxed shape assumed by a bag tube of generally flexiblematerial such as kraft paper. Thus, the walls of the tube will tend torest adjacent each other under the influence of gravity while the endsof the tube do not necessarily have a distinct longitudinal fold line. I

The tube blanks are transported through the bag making machine bysuitable conveyor means such as endless belts 13, 14 which incorporatesuitable grasping means for holding the tube blanks.

A stationary machine frame 15 is illustrated which includes a suitablebed upon which the endless belts l3, 14 move. A stationary g'uide bar 16is provided positioned essentially transverse to the machine directionbeneath which the end of the bag tubes are transported. Adjacent the bar16 is a cam plate 17 having a gradually inclining curved surface whichrises to a perpendicular relationship with the plane of travel of thebag tubes. Thus, as the bag tubes pass over the cam plate 17 the tubeend is folded along a line transverse to the tube and essentiallyperpendicular to the plane of the tube. Therefore, an upstanding end 19,of the tube, is formed.

For brevity, the conventional scoring drums have been omitted fromFIG. 1. These provide the several score lines required to define thevarious fold lines. for forming the overlying layers of the tube end toserve as the bag bottom. The scoring drums are generally positioned inthe machine ahead of the cam plate 17 so that the scoring is performedprior. to folding the upstanding end 19.

The fold formed by the cam 17 is not exceptionally sharp so thata smallradius is left at the fold line. Thus, the upstanding end 19 is ofsomewhat relaxed condition depending upon the weight of paper stock usedand defines a plane of somewhat variable width parallel to the machinedirection. The plane is somewhat thicker at the end of the tube than itis in the central region where the walls tend to rest adjacent eachother.

Several further operations, not illustrated, are required to form thebag. The upstanding end is first spread open then flattened back intothe plane of the tube leaving exposed the inner surfaces of the tubeend. Then, adhesive is applied to the exposed inner surfaces and theyare again folded to provide secured overlying layers. Appropriateapparatus for performing these functions is illustrated in theaforementioned patent US. Pat. No. 2,707,421.

As illustrated in FIG. 1, the prior art method of preopening the bagtube end employs a pair of suction cups rigidly rotated by a pair ofdriven shafts 21, 22 which are quidistantly disposed on either side ofthe path of passage of the upstanding tube end 19 and paralleltherewith. For supporting the shafts 21, 22 the machine frame includesan overhead frame member 23 having downwardly depending bearing bosses24, 25. The

bosses include suitable bearings in which the shafts 21,

22 rotate. Also, the bosses 24, 25 respectively include stationary arms26, 27 which depend from the lower ends thereof. Mounted for rotationabout horizontal axes in the arms 26, 27 are a pair of shafts whichrespectively include bevel gears 28, 29. These respectively engage bevelgears 30, 31 keyed to the shafts 21, 5 22. The shafts of the bevel gears28, 29 have fixed to their respective ends bow-shaped forming members32, 33 for concurrent rotation thereof in essentially vertical planes.Non-rotatably connected to the lower ends of the shafts 21, 22 are apair of opposing suction cups.

The shafts 21, 22 are driven in synchronism at equal angular speed andin equal opposite directions such that the scution cups associatedtherewith are opposite each other when a bag blank is present betweenthe shafts 21, 22. Thus, the suction cups make a tangential 5 passagealong the upstanding end 19 while both cups are moving in essentiallythe same direction as the tube end. The tangential passage can bearranged so that there is some interference i.e., the cups willconcurrently apply some force on each other as the tube end is trappedbetween them. Or, the tangential passage can be adjusted to have someclearance so that suction cups are not subjected to any mechanicalpressure as they jointly contact the bag tube.

A cam operated pneumatic valve 40 is schematically illustratedmechanically coupled with the drive means for driving the shafts 21, 22.A vacuum source 41 is connected with the valve 40. The shafts 21, 22 arehollow thereby providing a passageway communicating with the rotatingsuction cups. The upper ends of the shafts 21, 22 include appropriaterotating vacuum couplings, not shown, and a pneumatic tube connection,not shown, connected with the pneumatic valve 40 for receiving a vacuumpressure. The cam operated pneumatic valve is arranged to apply a vacuumto the shafts 21, 22 the moment the suction cups approach the tube endwalls. The vacuum pressure is kept on for a short period of time as thesuction cups pull away from each other partially opening the tube end.The vacuum is then immediately shut off to prevent tearing of the tubewalls. This is required since the circular path of motion of the suctioncup faces provides a velocity thereof which is in agreement with thevelocity of the tube end only at the point of contact.

The bow-shaped forming members 32, 33 are axially offset slightly sothat the ends thereof are one behind the other in the machine direction.These ends immediately enter the partially opened tube end spreading itfurther to a fully opened condition into the plane of the tube exposingthe inner surfaces thereof.

A major disadvantage of this prior art method and apparatus for openingthe tube end arises from the fact that the faces of the suction cups areconstantly changing their angular relationship whereby they are parallelwith each other at only one point in their paths of motion, namely, thepoint of contact with the tube end. As a result, it has been necessaryto adjust their respective radius arms of rotation such that theirtangential passage is one involving interference, or mechanical pressurewith each other and the tube end, in order to minimize the number ofimproperly formed bags. As indicated above this measure has not provedentirely satisfactory.

Referring now to FIG. 2 which is a cross-sectional view along the lines2-2 of FIG. 1 wherein the tube end opening device is modified to includefeatures of the present invention, the depending stationary boss 25 islengthened in a downward direction and includes an opening 45 toaccompany the bevel gear 29. A solid shaft 52 is used in place of thehollow shaft 22 and has suitably keyed to its upper end a drivengear-53. A suction cup 54 is shown in which is fitted a vacuum line 55.

Referring now jointly to FIG. 3 and 4, several axes of rotation areidentified. A first axisof rotation is occupied by a shaft 56 to whichis fixed the suction cup 54. The second axis of rotation is occupied bythe shaft 52.

v The third axis of rotation is occupied by a shaft 57 the lower end ofwhich is fixedto a suction cup 58. The

' fourth axis of rotation is occupied by a shaft 59 which mechanism. Thesame common drive is used to operate the cam, not shown, associated withthe cam operated pneumatic valve 40.

The shaft 52 is rotateably mounted in the overhead frame 23 withbearings 63, 64. The lower bearing 64 is directly fitted into acounterboard portion of the boss 25. The upper bearing 63, is fitted ina bearing retaining ring 65 which is, in turn, fitted into a matingcounter bore in the overhead frame member.

A second counter bore is provided in the lower surface of the boss intowhich is snugly fitted the hub end of a gear 68. The counter bore isarranged concentric with the axis of the shaft .52 so that the pitchdiameterof the gear 68 is generally concentric with the shaft 52. A setscrew 69 is employed to secure the gear 68 in non-rotatable relationshipwith the boss 25. a support member 70 is clamped to the lower end of theshaft 52 with a clamping screw 71. A slot is provided in the wall of thesupport member 70 to obtain the de-' sired clamping action. An idlergear 73 is provided which is rotateably mounted to the support memberfor engagement with the stationary gear.68 .-The idler, in turn, isengaged with a gear 74 which is rotateably mounted in the support member70. More specifically,

- the gear 74 is clamped to the shaft 56 with a gear clamp and screw 75.An extended hub portion of the gear 74 is provided over the end portionof which the gear clamp 75 is fitted. Also, this hub is fitted "inbearings 76,

v 77 which are, in turn, fitted in the support member 70 to'permitrotation of the shaft 56 with respect to the support member. The suctioncup 54 is fixed to the lower end of the shaft'56.

- As the gear 53 is driven by the machine common drive mechanism itrotates the shaft 52 which carries with it the support member 70so thatthe first axis of rotation. occupied by the shaft .56-is caused torotate about the shaft 52 in acircular path. As shown in FIG.

j 4, the direction of rotationof the-gear 53 and the suppoi-t member 70illustrated clockwise. The idler gear 73 is caused to rotate by thestationary gear 68 as its pivotal axis is carried around the gear 68 bythe support member 70. The idler 73, in tum, drives the gear 74 in I acounter clockwise direction, resulting in a counter clockwise movementof the shaft 56 with respect to its axis. The gears 68 and 74 have thesame number of ;teeth so that for each clockwise revolution of thesupport member 70 the shaft 56 makes counter clockwise revolution. Thus,the angular velocity of the shaft 56 about the axis of the shaft 52 isequal to but opposite in direction of the angular velocity of thesuction cup 54'with respect to the shaft 56.

It is seen that the suction cup 54 moves in a circular path whilemaintaining constant the angular relationship of the plane of its facewith respect to the machine frame.

The Suction cup 58 is driven by an identical but mirror image mechanismof that used for driving the-cup 54. The gears 53, 60 and the centerdistances between the shafts 52, 56 and 57, 59 are selected to provide aperipheral speed of the faces of the cups 54, 58 approximately equal tothe speed of movement of the tube end at the point of tangentintersection with the tube end. It can be understood that due to theimproved performance of the suction cups wide tolerances of this speedare found acceptable.

Also, the cups 54 and 58 are initially set up parallel with each otherand with the path of movement of the tube ends by adjustments of theclamp and screw 75.

Likewise, reasonably wide tolerances of this angular relationship areacceptable since, once established, the angular relationship areacceptable since, once established, the angular relationships of thecups remain unchanged as they are moved through .their respective paths.I have found that an angular tolerance from parv allel of 10 to be quiteacceptable.

The cam operated pneumatic valve 40 is preferably arranged tosimultaneously apply a vacuum pressure to the suction cups approximately5 of theirrespective rotation about the shafts 52, 59 prior to being vopposite I It is preferred that the shafts 52, 56, 57, and 59 bearranged generally perpendicular to the bed of the machine. so that thecups 54, 58. move 'generally in the same direction as the tube ends atthe point of their tangential passage. However, I have found that thepresent invention makes possible very wide variations from thispreferred design. Indeed, acceptable performance is obtained if themovement of the suction cups merely has a vector component in the samedirection as the tube end direction of movement when making thetangential passage. Also, wide tolerances of the nature of thistangential passage can be absorbed. It can be a passage of the cups inwhich only brushing contact is made with the tube walls or one whichinvolves a substantial pressure between the two cups with the tube wallstherebetween. Thus, as used herein; the term tangential passage isintended to embrace a family of arcs of movement of the cups which. comenear the tube end walls or which intersect with them.

In a specific example the gears 68 and 74 were selected having a pitchdiameter of 2% inches. A pitch diameter of 1% inches was chosen for theidler gear 73 and it was positionedto provide a center distance, Rbetween the shafts 52 and 56 of 2% inches. The radius of movement of theface of the cup with respect to the shaft 56, R waschosen-as 2% inches.The cups were placed to provide approximately aline-to-line conditionthereof without a'bag' tube present at'the nearest point of theirtangential passage.

It can be seen by those skilled'in the art that the path of movement ofthe suction cup 54 with respect to the machine frame is a circle ofradius R with'its axis displaced toward the bag tube end by a distance Rfrom the axis of the shaft 52. Thus, the preferredangular speed of thegear 53 can be easily calculated to'provide a peripheral speed at aradius R approximately equal to the speed of the bag tube end. I

By employing the tube end opening device hereinabove described it becamepossible to substantially increase the speed of the bag forming machinewhile lowering to substantially zero the rate of malformed bagsattributable to improper end opening.

While the invention has been described with a certain degree ofparticularity it can, nevertheless be seen, by the examples hereinaboveset forth, that .many variations and modifications of the invention canbe. made without departing from the true. spirit 'and scope thereof.

1 claim: 1 I

1. In combination with apparatus for forming a closed bottom of a bagfrom an'essentially flat'tube of flexible material including a machineframe, means in said frame for folding the endof said tube to provide aplurality of overlying layers thereof while said end is in motion, meansin said frame for moving said end of said tube into said folding meansin-apredetermined direction for said folding, and means operativelycoupled with said folding means for securing said overlying layers toform said bag bottom, apparatus operatively coupled with said foldingmeans for opening said end of said tube while said end is in motion insaid direction prior to completion of said folding thereof, comprising:

a. a first suction cup; r

b. a support member;

0. means for rotating said suction cup at a predetermined angularvelocity about a first axis which is positioned in said support member,said means including a single pivotal connection means on said suctioncup for rotatable connection thereof with said support member and fordefining said first axis;

d. means for rotating said support member at an angular velocitysubstantially equal to but opposite in direction to said angularvelocity provided by said means (c) about a second axis, said secondaxis being positioned to provide a first essentially tangential passageof the suction face of cup with a first wall of said tube end insubstantially the same direction as said predetermined direction ofmovement of said tube end; and

e. means for applying a suction pressure to said suction cup at least inpart during said tangential passage of said suction cup face with saidfirst wall.

2. The appartus of claim 1 further comprising:

f. a second suction cup;

g. a second support member;

h. means for rotating said second suction cup at a predetermined angularvelocity about a third axis, said third axis being positioned in saidsecond support member, said means (h) including a single pivotalconnection means on said second suction cup for rotatable connectionthereof to said second support member and for defining said third axis;

synchronism with said means (d) at an angular velocity substantiallyequal to but opposite in direction to said angular velocity provided bysaid and concurrent with said first tangential passage of I said firstcup; and j. means for applying a suction pressure tos aid second suctioncup at least in part during said second tangential passage of saidsecond cup face with said 'second wall.

31in combination with apparatus for' forming a closed bottom of a bagfrom an essentially flat tube of flexible material including a machineframe, means in said frame for folding the endof said tube to provide aplurality of overlying layers thereof while said tube end is in motion,means in said frame for moving said. tube end into said folding meanswith a predetermined 1 velocity for said folding, and means operativelycoupled with said folding means for securing-said overlying layers toform said bag bottom, apparatus operatively coupled with said foldingmeans for opening said tube end while it isin motion at said velocityprior to completion of said, folding thereof, comprising:

a. a first support member; 1 b. a second support member; p V g c. firstand second opposing suction cups, one on each side of the path ofmovement of said end of said tube in said frame, said first suction cuphaving a single pivotalconnection means thereon defining a first axis ofrotation for rotatable mounting of said first suction cup to said-firstsupport member; (1. means for rotating said first suction cup about saidfirst axis in a first angular direction at a first angular speed;

e. mounting means for rotatably mounting said first support member tosaid frame for rotation thereof 1 about a second axis essentiallyparallel to said first axis, wherein said mounting means is positionedin said frame to provide a first tangential passage of the face of saidfirst suction cup with a first wall of said tube end in a' directionsubstantially aligned with the direction of movement of said tube end;f. means for rotating said first support member about said second axisat an angular speed essentially equal to said first angular speed and inan angular direction essentially opposite to said first angular Ydirection; r i g. a single pivotal connection means on said secondsuction cup for rotatable connection thereof to said second supportmember, said single pivotal connection means defining a thirdaxis ofrotation;

h. means for rotating said second suction cup about said third axis atan angular speed substantially equal to said first angular speed and inan angular direction essentially opposite to said first angulardiection;

i. mounting means for rotatably mounting said second support member tosaid frame for rotation thereof about a fourth axis essentially parallelto said third axis wherein said mounting means (i) is positioned in saidframe to provide an essentially means for rotating said second supportmember in Y tangential passage of the face of said second cup with thewallof said tube end oppositesaid first wall but in the vicinity of saidfirst tangential passage and in a direction substantially aligned withthe direction of movement of said tube end; and

- j. means for rotating, in synchronism with the rotation of said firstsupport member, said second support member about said fourth axis at anangular speed essentially'equal to said first angular speed and in anangular directionessentially the same as said first angular direction.

4. In combination with apparatus for forming a closed bottom of a bagfroman essentially flat tube of flexible material including a machineframe, means in said frame for folding the end of said tube to provide aplurality of overlying layers thereof while said end is in motion, meansin said frame for moving said end of said tube into said folding meansin a predetermined direction for said folding, and means operativelycoupled with said folding means for securing said overlying layers toform said bag bottom, apparatus operatively coupled with said foldingmeans for opening said end of said tube while said end is in motion insaid direction prior to completion of said folding therof, comprising:

a. a suction cup;

b. a support member;

c. a toothed driven member fixed to said suction cup and rotatablymounted to said support member for defining a first axis of rotation ofsaid suction cup with respect to said support member;

(1. means for rotating said support member about a second axis,saidsecond axis being positioned in said machine frame substantiallyparallel to said first axis and positioned in said machine frame toprovide a first essentially tangential passage of the suction face ofsaid cup with a first wall of said tube end in substantially the samedirection as said predetermined direction of movement of said tube end;

e. a toothed driving member fixed to said machine frame in a positioncircumscribing said second axis;

f. engagement means for engaging said driven member (c) with saiddriving member (e) to rotate said suction cup about said first axis in adirection opposite to the direction of rotation of said support member;and

g. means for applying a suction pressure to said suc tion cup at leastin part during said tangential passage of said suction cup face withsaid first wall.

'5. The apparatus of claim 4 further comprising:

h. a secondv suction cup;

i. a second support member;

j. a second toothed driven member fixed to said second suction cup androtatably mounted to said second support member for defining a thirdaxis of rotation;

k. means for rotating said second support member about a fourth axis,said fourth axis being positioned in said machine frame essentiallyparallel to said third axis and positioned in said machine frame toprovide an essentially tangential passage vof the suction face of saidsecond cup with a second wall of said tube end in the vicinity of,substantially in the same direction and concurrent with said firsttangential passage of said first cup;

. a second toothed driving member fixed to said machine frame in aposition circumscribing said fourth axis;

m. engagement means for engaging said driven member (j) with. saiddriving member (1.) to rotate said second suction cup about said thirdaxis in a direction opposite to the direction of rotation of said secondwall.

1. In combination with apparatus for forming a closed bottom of a bagfrom an essentially flat tube of flexible material including a machineframe, means in said frame for folding the end of said tube to provide aplurality of overlying layers thereof while said end is in motion, meansin said frame for moving said end of said tube into said folding meansin a predetermined direction for said folding, and means operativelycoupled with said folding means for securing said overlying layers toform said bag bottom, apparatus operatively coupled with said foldingmeans for opening said end of said tube while said end is in motion insaid direction prior to completion of said folding thereof, comprising:a. a first suction cup; b. a support member; c. means for rotating saidsuction cup at a predetermined angular velocity about a first axis whichis positioned in said support member, said means including a singlepivotal connection means on said suction cup for rotatable connectionthereof with said support member and for defining said first axis; d.means for rotating said support member at an angular velocitysubstantially equal to but opposite in direction to said angularvelocity provided by said means (c) about a second axis, said secondaxis being positioned to provide a first essentially tangential passageof the suction face of cup with a first wall of said tube end insubstantially the same direction as said predetermined direction ofmovement of said tube end; and e. means for applying a suction pressureto said suction cup at least in part during said tangential passage ofsaid suction cup face with said first wall.
 2. The appartus of claim 1further comprising: f. a second suction cup; g. a second support member;h. means for rotating said second suction cup at a predetermined angularvelocity about a third axis, said third axis being positioned in saidsecond support member, said means (h) including a single pivotalconnection means on said second suctiOn cup for rotatable connectionthereof to said second support member and for defining said third axis;i. means for rotating said second support member in synchronism withsaid means (d) at an angular velocity substantially equal to butopposite in direction to said angular velocity provided by said means(h), about a fourth axis, said fourth axis being positioned in saidframe essentially parallel to said third axis and positioned to providean essentially tangential passage of the suction face of said second cupwith a second wall of said tube end in the vicinity of, substantially inthe same direction and concurrent with said first tangential passage ofsaid first cup; and j. means for applying a suction pressure to saidsecond suction cup at least in part during said second tangentialpassage of said second cup face with said second wall.
 3. In combinationwith apparatus for forming a closed bottom of a bag from an essentiallyflat tube of flexible material including a machine frame, means in saidframe for folding the end of said tube to provide a plurality ofoverlying layers thereof while said tube end is in motion, means in saidframe for moving said tube end into said folding means with apredetermined velocity for said folding, and means operatively coupledwith said folding means for securing said overlying layers to form saidbag bottom, apparatus operatively coupled with said folding means foropening said tube end while it is in motion at said velocity prior tocompletion of said folding thereof, comprising: a. a first supportmember; b. a second support member; c. first and second opposing suctioncups, one on each side of the path of movement of said end of said tubein said frame, said first suction cup having a single pivotal connectionmeans thereon defining a first axis of rotation for rotatable mountingof said first suction cup to said first support member; d. means forrotating said first suction cup about said first axis in a first angulardirection at a first angular speed; e. mounting means for rotatablymounting said first support member to said frame for rotation thereofabout a second axis essentially parallel to said first axis, whereinsaid mounting means is positioned in said frame to provide a firsttangential passage of the face of said first suction cup with a firstwall of said tube end in a direction substantially aligned with thedirection of movement of said tube end; f. means for rotating said firstsupport member about said second axis at an angular speed essentiallyequal to said first angular speed and in an angular directionessentially opposite to said first angular direction; g. a singlepivotal connection means on said second suction cup for rotatableconnection thereof to said second support member, said single pivotalconnection means defining a third axis of rotation; h. means forrotating said second suction cup about said third axis at an angularspeed substantially equal to said first angular speed and in an angulardirection essentially opposite to said first angular diection; i.mounting means for rotatably mounting said second support member to saidframe for rotation thereof about a fourth axis essentially parallel tosaid third axis wherein said mounting means (i) is positioned in saidframe to provide an essentially tangential passage of the face of saidsecond cup with the wall of said tube end opposite said first wall butin the vicinity of said first tangential passage and in a directionsubstantially aligned with the direction of movement of said tube end;and j. means for rotating, in synchronism with the rotation of saidfirst support member, said second support member about said fourth axisat an angular speed essentially equal to said first angular speed and inan angular direction essentially the same as said first angulardirection.
 4. In combination with apparatus for forming a closed bottomof a bag from an essentially flat tube of flexiblE material including amachine frame, means in said frame for folding the end of said tube toprovide a plurality of overlying layers thereof while said end is inmotion, means in said frame for moving said end of said tube into saidfolding means in a predetermined direction for said folding, and meansoperatively coupled with said folding means for securing said overlyinglayers to form said bag bottom, apparatus operatively coupled with saidfolding means for opening said end of said tube while said end is inmotion in said direction prior to completion of said folding therof,comprising: a. a suction cup; b. a support member; c. a toothed drivenmember fixed to said suction cup and rotatably mounted to said supportmember for defining a first axis of rotation of said suction cup withrespect to said support member; d. means for rotating said supportmember about a second axis, said second axis being positioned in saidmachine frame substantially parallel to said first axis and positionedin said machine frame to provide a first essentially tangential passageof the suction face of said cup with a first wall of said tube end insubstantially the same direction as said predetermined direction ofmovement of said tube end; e. a toothed driving member fixed to saidmachine frame in a position circumscribing said second axis; f.engagement means for engaging said driven member (c) with said drivingmember (e) to rotate said suction cup about said first axis in adirection opposite to the direction of rotation of said support member;and g. means for applying a suction pressure to said suction cup atleast in part during said tangential passage of said suction cup facewith said first wall.
 5. The apparatus of claim 4 further comprising: h.a second suction cup; i. a second support member; j. a second tootheddriven member fixed to said second suction cup and rotatably mounted tosaid second support member for defining a third axis of rotation; k.means for rotating said second support member about a fourth axis, saidfourth axis being positioned in said machine frame essentially parallelto said third axis and positioned in said machine frame to provide anessentially tangential passage of the suction face of said second cupwith a second wall of said tube end in the vicinity of, substantially inthe same direction and concurrent with said first tangential passage ofsaid first cup; l. a second toothed driving member fixed to said machineframe in a position circumscribing said fourth axis; m. engagement meansfor engaging said driven member (j) with said driving member (l) torotate said second suction cup about said third axis in a directionopposite to the direction of rotation of said second support member; andn. means for applying a suction pressure to said second suction cup atleast in part during said second tangential passage of said second cupface with said second wall.